Three finger compliant gripper based on topology optimization

  Scheme for the development of the model of a two-finger gripper Copyright: © Estefania Hermoza Llanos

Project State



Compliant mechanisms are monolithic mechanical entities that can transmit motion and forces through deflection of their flexible parts.

With this premise, it is possible to replicate the functionality part of a human finger with such compliant monolithic mechanisms.



A compliant three-finger gripper could be employed in several fields, for example medical and automation, for a variety of taks such as assembly, transportation and sample collection, precision manipulation and others. The design, being monolithic, can be miniaturized and actuated in small scales without losing precision; moreover, the mechanism can be used in assembly of small parts, sample collection, automation of some process that involves grasping of delicate objects, pick-and-place, and others tasks that involves high precision.


The goal is to present the design, working prototype and control of a three finger compliant gripper, which has fully compliant fingers undergoing large deformations. Each finger will have two degrees of freedom: extension and flexion, and abduction and adduction.



In order to achieve the design of a three compliant finger gripper, the first step is to develop the design of each finger through topology optimization and Hill Climbing mutation algorithm, then the motion and deflection of each finger will be tested with prototypes made with 3d Rapid prototyping. Once the design of the fingers is ready, a complete design of the configuration of the gripper will be developed, this includes the design of a compliant mechanism that will allow the degree of freedom of abduction and adduction. Finally, the last step will be to model the mechanism according to the actuation method and achieve an active control of it.

An iterative approach was taken to the development and testing of the prototypes, with individual fingers being developed first, followed by a two-finger gripper and finally a three-finger gripper, which was manufactured as a prototype for various application scenarios.

  Model of Three Finger Gripper Copyright: © Estefania Hermoza Llanos Development of the first prototype of a three finger compliant gripper based on topology optimization
Two Finger Gripper